MET-EGFR dimerization in lung adenocarcinoma is dependent on EGFR mtations and altered by MET kinase inhibition

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Advanced lung cancer exhibits poor survival and limited therapeutic options.
• Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective but acquired resistance is common, often due to the T790M mutation or MET amplification.
• Preclinical studies suggest a synergistic effect between MET and EGFR inhibitors.

Purpose of the Study:

• To investigate the hypothesis that EGFR-MET dimerization, influenced by EGFR mutation status, dictates response to MET inhibition.
• To evaluate the efficacy of a MET TKI (SGX523) in isogenic cell lines with different EGFR genotypes.
• To correlate treatment response with EGFR-MET dimerization dynamics.

Main Methods:

• Generation of isogenic NCI-H1975 cell lines: H1975L858R/T790M (resistant), H1975L858R (sensitized), and H1975WT (wild-type).
• Assessment of cell proliferation in vitro and tumor growth/stroma formation in xenograft models treated with SGX523.
• Measurement of EGFR-MET dimerization using Förster Resonance Energy Transfer (FRET).

Main Results:

• SGX523 significantly inhibited proliferation and tumor growth in H1975L858R/T790M cells, decreasing ERK phosphorylation.
• SGX523 showed limited efficacy in H1975L858R and H1975WT cells, only reducing stroma formation in H1975L858R cells.
• SGX523 reduced EGFR-MET dimerization in H1975L858R/T790M cells but induced it in H1975L858R cells, with no effect in H1975WT cells.

Conclusions:

• MET inhibition efficacy is determined by EGFR genotype, specifically through modulation of EGFR-MET heterodimerization.
• EGFR-MET dimerization dynamics, rather than MET copy number alone, appear critical for MET inhibitor response.
• These findings suggest that EGFR genotype-specific targeting of MET could be a viable therapeutic strategy in lung cancer.